Which is the most difficult language in the world,do you think to speak?

[NYCGori]

Try bushmen for a change. They even have the letter "!" which is like opening a coke bottle sound - called a click. What the actual language called again? Bushmen language?

I think you're thinking of the people that live in the Kalahari desert of SW Africa, the Saan. There are a few other languages spoken in southern Africa that also use clicks, as well.